The present invention relates to torque converters employed in the drivetrain of vehicles, and more particularly to multiple torque converters employed in a single drivetrain.
Conventionally, automotive vehicles where powered with an internal combustion engine only. More recently, some automotive vehicles are powered with what is called a hybrid system. This hybrid system often includes an internal combustion engine that operates in parallel with a motor, with either or both supplying the torque to the transmission. For completely new vehicles, one can account for the different packaging space required for these hybrid powertrains, but for existing vehicles, it may only be economically feasible to fit the hybrid system within the packaging space originally allowed for the conventional system. This packaging problem can be particularly difficult to overcome with a transverse engine, front wheel drive, automatic transaxle configuration. Now, where conventionally an engine, torque converter, and transaxle (or transmission if rear wheel drive) were located, there also needs to be space for a motor.
Thus, it is desirable to have a vehicle powertrain that overcomes the drawbacks of the conventional torque converter configuration by allowing flexibility in packaging the torque converter between an engine and a transmission or transaxle.
In its embodiments, the present invention contemplates a torque converter assembly for receiving torque from an engine crankshaft assembly and transmitting torque to a transmission input shaft. The torque converter assembly includes a first torque converter sub-assembly having a first impeller adapted to be rotationally driven by the crankshaft assembly, a first turbine mounted adjacent the first impeller and drivable thereby, the first turbine adapted to be rotationally coupled to the transmission input shaft, and a first stator mounted between the first turbine and the first impeller. The torque converter assembly also includes a second torque converter sub-assembly having a second impeller rotationally coupled to the first impeller, a second turbine mounted adjacent the second impeller and drivable thereby, the second turbine rotationally coupled to the first turbine, and a second stator mounted between the second turbine and the second impeller. A first one-way clutch is rotationally coupled to at least one of the first stator and the second stator, and a stator shaft, which is rotationally fixed, is coupled to the first one-way clutch.
An embodiment of the present invention allows a tandem torque converter assembly to produce the torque of a conventional torque converter, while allowing for a reduced diameter of the torque converter assembly.
An embodiment of the present invention allows a tandem torque converter assembly to produce the torque of a conventional torque converter, while allowing for a reduced length of the torque converter assembly.
An advantage of the present invention is that the overall torque converter assembly can be made a smaller diameter or a shorter length in order to allow for packaging a motor in parallel with an engine in a hybrid powertrain type of arrangement.
Another advantage of the present invention is that a tandem torque converter arrangement can be employed to allow for a smaller diameter or a shorter length when employed with only a conventional engine, if packaging space within the vehicle engine compartment so requires.